Bullying came up as a topic on the radio the other day as I drove to daycare. A new documentary is coming out called Bully. The subject is unsettling for a relatively new parent like me. I’ve had glimpses into the potential future when I catch sight of my daughter getting pushed over by one of the other kids in the playground or at daycare. (Not that she is innocent herself when it comes to pushing and shoving as my son would point out if he were old enough to talk).
Bullying is a topic that certainly weighs on the minds of a lot of parents. But is it a public health issue? When it comes to public health, I usually think of infectious disease problems first – like monitoring flu cases or investigating outbreaks of food poisoning. After that I think of chronic disease surveillance – like tracking cancer and obesity rates. I was surprised to learn that the Centers for Disease Control and Prevention (CDC) collects data on bullying as part of their work in the National Center for Injury Prevention and Control.
The CDC fact sheet on bullying highlights the public health implications of this problem, describing the potential for “physical injury, social and emotional distress, and even death” that can result from bullying behavior. Studies like this one from England have found higher rates of headaches, abdominal pain and sleep problems in kids who were bullied. A new study from the Canadian Journal of Public Health explored the relationship between bullying and another important health outcome – depression.
The study collected survey data on middle school students in a medium-sized Canadian city. The survey was based in part on prior work done by the World Health Organization. A total of 4,197 students completed that survey (nearly half of those eligible).
In this study group, almost 1 out of every 4 students reported being physically bullied at least once in the previous month. Nineteen percent of the students were physically bullied once or twice a month and 4% were bullied every week.
Males attending a school in a low-income neighborhood were more likely to have been bullied. Bullying was also more common in those students who said that there home life was unhappy and that they had a lot of arguments with their parents.
Those who were bullied many times per week were over 4 times more likely to be depressed than students who were never bullied. Depressed mood was more likely in those who were bullied even when other factors (like self-esteem, parental relationship and home life) were taken into account.
The study authors acknowledge that because the data is observational and collected at 1 point in time, it is not possible to prove a causal relationship between bullying an depression. It could be that depressed students are more likely to be bullied and not that bullying leads to more depression.
Even though the data is cross-sectional (obtained by observation at a single point in time), the results show a dose-dependent relationship between bullying and depression, which provides some support for concluding that the relationship is causal. Dose-dependent means that as the amount of bullying increased so did the rates of depression (8.1% of those never bullied were depressed, 16% of those bullied once or twice a month, 26% of those bullied weekly, and 37.3% of those bullied multiple times per week).
This study adds support to the perspective that views bullying as a public health issue and helps to define the extent of the problem and the consequences. The next steps in a public health response are to develop and test prevention strategies.
The CDC fact sheet notes that “research on preventing and addressing bullying is still developing”. Some results are available and have shown, for instance, that comprehensive “whole school” interventions that involve multiple disciplines and encompass the entire school community are more effecitve than small scale curriculum based interventions. More studies are needed. Efforts to fill this gap are moving forward and public health officials will continue to contribute.